code: def run(self) -> None:
      while not self._finished:
          time.sleep(self._sleep_period)
          self._finished = self._run()
  
imports: import logging
  import os
  import signal
  import subprocess
  import sys
  import threading
  import time
  from typing import Any, Callable, List, Optional, Sequence, Tuple
  from lightning_utilities.core.imports import RequirementCache
  from typing_extensions import override
  from lightning.fabric.plugins.environments.cluster_environment import ClusterEnvironment
  from lightning.fabric.strategies.launchers.launcher import _Launcher
  from lightning.fabric.utilities.distributed import _set_num_threads_if_needed
  from lightning.fabric.utilities.rank_zero import rank_prefixed_message
label_desc: Use image node_id 2 for calling the _ChildProcessObserver obj's underlying member method code with example usage: obj.run() without return types